1. Field of the Invention
This invention relates to an image forming apparatus for forming an image as with a printer or a copying device on blank surfaces of recording papers whose one-side surfaces have been already used for recording information such as of characters.
2. Description of the Prior Art
In recent years, the volume of consumption of quality paper has been increasing at a fairly high rate in consequence of conspicuous dissemination of such office automation devices as copying devices and printers. In the meantime, reckless deforestation has been raising a global ecological issue. Enterprises which are relatively large paper consumers, anxious about this grave situation and eager to make further use of those papers which have been used for printing or copying information on only one-side surfaces thereof with a printer or a copying machine, have come to follow the practice of making full use of the blank surfaces of these used papers.
When the blank surfaces of the used papers are utilized for printing characters or color images with a printer or copying information with a copying device and when the image information newly recorded on the blank surfaces of the used papers bears similarity to the image information previously recorded on the one-side surfaces of the papers, these papers have the possibility of defying clear distinction between the surfaces bearing a newly recorded image information and those bearing a formerly recorded image information. The confusion of this nature may not occur immediately after the printing of the new image information is completed. Once the papers having image information recorded on both the opposite surfaces thereof are filed, a person trying to retrieve necessary image information from the file may be possibly prevented from easily discriminating between the opposite surfaces of the papers.